This invention relates to film drive assemblies for photographic printers.
Commercial photographic processing laboratories require the capability of making vast numbers of photographic prints from equally large numbers of photographic negatives. The photographic negatives are typically handled in long roll form and are processed in photographic printers by mounting the long roll of negative film on mechanized film drives. The photographic printers may operate in both automated or semi-automated environments.
Most film drives for use with these photographic printers are either electrically or pneumatically powered. A continuous roll of exposed and developed photographic film is mounted on the feed spool of the film drive and routed across the optical stage of the photographic printer. Individual negative frames are sequentially positioned at the optical stage of the photographic printer by operation of the drive components of the film drive so that one or more photographic prints can be made from each frame under either operator or machine control. Finally, the film is collected on a film take-up spool of the film drive.
Because photographic film is manufactured in a variety of different widths, a film drive needs to be capable of variably laterally positioning the film in relation to the photographic printer so that the longitudinal center line of the various widths of photographic film can be positioned to correspond with the optical center of the photographic printer. And because each frame of a roll of photographic film requires individual cropping, a film drive further must be capable of variably positioning each frame of a roll of film of a given width in a longitudinal sense. The film drive also desirably provides the ability to expose the individual film frames in either a landscape format or a portrait format.
Various film drives are available that satisfactorily perform all of the above-described functions. See, for example, the film drives disclosed in applicant's U.S. Pat. Nos. 5,343,272, 5,146,266 and 5,097,292.
However, there still exists a need to adjust the film as it is being processed in a manner to compensate for exposures that are unwantedly tilted with respect to horizontal or vertical references.